Coronary artery disease remains the leading cause of morbidity and mortality in Western societies. Narrowing or blockage of the coronary arteries often results in myocardial ischemia and infarction. Different approaches have been developed for treating coronary artery disease, including balloon angioplasty, atherectomy, laser ablation, stents, and coronary artery bypass grafting surgery. Excellent long-term results have been achieved with conventional coronary bypass surgery. However, significant mortality and morbidity still exist due to the use of cardiopulmonary bypass for circulatory support and the traditional method of access by median sternotomy.
Minimally invasive concepts have been adopted in cardiac surgery to make coronary revascularization less invasive. In the port-access approach, a cardiac procedure is performed through minimal access incisions often made between a patient's intercostal space and cardiopulmonary support is instituted through an extra-thoracic approach.
In both conventional and minimally invasive coronary artery bypass grafting surgeries, and other cardiac surgeries such as heart valve repair or replacement, septal defect repair, pulmonary thrombectomy, atherectomy, aneurysm repair, aortic dissection repair and correction of congenital defects, cardiopulmonary bypass and cardiac arrest are often required. In order to arrest the heart, the heart and coronary arteries must be isolated from the peripheral vascular system, so that cardioplegia solution can be infused to paralyze the heart without paralyzing the peripheral organs. Cardiopulmonary bypass is then initiated to maintain peripheral circulation of oxygenated blood.
In conventional coronary artery bypass surgery, cardioplegia solution is usually administered through a catheter inserted into the aorta. Problems associated with this approach are that an additional wound site is generally required for administering cardioplegia, and that a cardioplegia catheter, located in the vicinity of the surgical field, may interfere with a surgeon's operation. Retrograde administration of cardioplegia to the coronary sinus as an alternative approach has been shown to be beneficial to the heart. In minimally invasive coronary artery bypass surgery, placement of a cardioplegia catheter often requires fluoroscopic guidance, and circulatory isolation of the heart and coronary blood vessels generally involves insertion of multiple large catheters in either the neck, or the groin, or both to remove blood from the superior vena cava and inferior vena cava for cardiopulmonary bypass. Problems with this procedure are that excess catheterization and use of fluoroscopy may be associated with increased morbidity.
New devices and methods are therefore desired for isolating the heart and coronary blood vessels from the peripheral vascular system and arresting cardiac function, particularly devices which do not require multiple cannulation sites, fluoroscopy, and/or additional cardioplegia catheter insertion.